Giant intracranial aneurysms: morphological characterization and clinical correlation

Abstract

Intracranial aneurysms are acquired dilatations of intracranial arteries located mainly at the arterial branching points near to the skull base. Objective: The purpose of this study was to characterize morphologically giant intracranial aneurysms aiming correlation with clinical presentation. Method: A total of 80 patients with giant intracranial aneurysms, 14 (17.5%) males and 66 (82.5%) females, were studied from January 2001 to January 2009 at the Vascular and Endovascular Neurosurgery Unit of the Hospital de Base of Sao Jose do Rio Preto, SP. Univariate and multivariate analyses were made to test the associations among demographic (sex and age), morphological (anatomical localization, type, quantity, laterality, and size), and clinical features (focal neurological deficit, seizure, headache, sudden headache, visual disturb, cavernous sinus syndrome (CSS), facial palsy, Hunt and Hess scale at diagnosis, Fisher's grading system). The protective effect against rupture of the giant aneurysm according to the vascular pattern of communicating arteries (good quality as patent communicating arteries or quality as hypoplasia or agenesis of communicating arteries) was analyzed using chi-square test by analysis of dependency. Results: The main locations of the unruptured giant aneurysms included the carotid cavernous (35.7%) and supraclinoid (28.6%) arteries and the ruptured aneurysms the most frequent were carotid supraclinoid (33.3%) and middle cerebral (29.2%) arteries. Of all giant aneurysms, the type was saccular in 85% and fusiform in 15%. The main clinical presentations at the moment of diagnosis were headache (44.6%) and CSS (30.4%) in unruptured aneurysms and sudden headache (100%) and focal neurological deficit (12.5%) in ruptured aneurysms. There was a significant association among vascular pattern of communicating arteries of bad quality and presence of thrombus and calcification (p=0.005). The risk of rupture of giant aneurysms in relation to the presence of anterior and posterior communicating arteries of good quality is 8 times higher in patients with anterior and posterior communicating arteries of bad quality (OR 9.11, 95% CI 1.64 to 50.58; p=0.012) and 11 times higher in patients without thrombus and calcification (OR 12.73, 95% CI 0.98 to 165.99; p=0.05) when compared with patients with thrombus and calcification. Conclusions: Giant intracranial aneurysms are more frequent in segments of the internal carotid artery, mainly in the cavernous in unruptured aneurysms. There is a high rupture risk of giant aneurysms in the region of the middle cerebral artery. In the region of the anterior cerebral artery the frequency of aneurysms is low. The increase in the size of giant aneurysms coincides with an increase in the Fisher's grading system. In giant aneurysm, communicating arteries of bad quality are associated with presence of thrombus and calcification. The rupture risk is significantly higher in patients without thrombus and calcification in relation to those with thrombus and calcification.